1. Field of the Invention
The present invention generally relates to an image forming apparatus, and, more particularly, to an image forming apparatus that electrically monitors the residual developers collected in a collecting box.
2. Description of the Related Art
In an image forming apparatus using electronic photographic technology, after forming an image, a developer remaining on an image-formed medium is normally removed by a blade for use in the next image forming process. The removed, residual developer is collected through a conveying screw in a collecting box. When the amount of the residual developers in the collecting box reaches the maximum collecting amount, it is displayed that the collecting box is full.
Conventionally, to detect that the amount of the residual developers reaches the maximum collecting amount, a micro switch is provided adjacent one end of the conveying screw so that it is turned ON when the conveying screw moves in the thrust direction at the time the collecting box becomes full of residual developers.
According to the above conventional detector, however, because of movement of the conveying screw allowed, a gap between the screw and a bearing section for supporting the screw cannot be sealed. Therefore, the developer is likely to leak from this gap. Further, since the movement of the conveying screw in the thrust direction is not constant, the level of detection will vary.